SQL Update Or Insert By Comparing Dates - sql

Question

I am trying to do the UPDATE or INSERT, but I am not sure if this is possible without using loop. Here is the example:
Says, I have this SQL below in which I joined two tables: tblCompany and tblOrders.
SELECT CompanyID, CompanyName, c.LastSaleDate, o.SalesOrderID, o.SalesPrice
, DATEADD(m, -6, GETDATE()) AS DateLast6MonthFromToday
FROM dbo.tblCompany c
CROSS APPLY (
SELECT TOP 1 SalesOrderID, SalesPrice
FROM dbo.tblOrders o
WHERE c.CompanyID = o.CompanyID
ORDER BY SalesOrderID DESC
) AS a
WHERE Type = 'End-User'
Sample Result:
CompanyID, SalesOrderID, SalesPrice, LastSalesDate, DateLast6MonthFromToday
101 10001 50 2/01/2016 10/20/2016
102 10002 80 12/01/2016 10/20/2016
103 10003 80 5/01/2016 10/20/2016
What I am trying to do is comparing the LastSalesDate and the DateLast6MonthFromToday. Condition is below:
If the LastSalesDate is lesser (earlier), then do the INSERT INTO tblOrders (CompanyID, Column1, Column2...) VALUES (CompanyIDFromQuery, Column1Value, Column2Value)
Else, do UPDATE tblOrders SET SalesPrice = 1111 WHERE SalesOrderID = a.SalesOrderID
As the above sample result, the query will only update SalesOrderID 10001 and 10003. And For Company 102, NO insert since the LastSaleDate is greater, then just do the UPDATE for the SalesOrderID.
I know it is probably can be done if I create a Cursor to loop through every record and do the comparison then Update or Insert, but I wonder if there is another way perform this without the loop since I have around 20K records.
Sorry for the confusion,

Answer 1

I don't know your tables structure and your data types. Also I know nothing
about duplicates and join ralationships between this 2 tables.
But I want only show how it works on next example:
use [your test db];
go
create table dbo.tblCompany
(
companyid int,
companyname varchar(max),
lastsaledate datetime,
[type] varchar(max)
);
create table dbo.tblOrders
(
CompanyID int,
SalesOrderID int,
SalesPrice float
);
insert into dbo.tblCompany
values
(1, 'Avito', '2016-01-01', 'End-User'),
(2, 'BMW', '2016-05-01', 'End-User'),
(3, 'PornHub', '2017-01-01', 'End-User')
insert into dbo.tblOrders
values
(1, 1, 500),
(1, 2, 700),
(1, 3, 900),
(2, 1, 500),
(2, 2, 700),
(2, 3, 900),
(3, 1, 500),
(3, 2, 700),
(3, 3, 900)
declare #column_1_value int = 5;
declare #column_2_value int = 777;
with cte as (
select
CompanyID,
SalesOrderID,
SalesPrice
from (
select
CompanyID,
SalesOrderID,
SalesPrice,
row_number() over(partition by CompanyID order by SalesOrderId desc) as rn
from
dbo.tblOrders
) t
where rn = 1
)
merge cte as target
using (select * from dbo.tblCompany where [type] = 'End-User') as source
on target.companyid = source.companyid
and source.lastsaledate >= dateadd(month, -6, getdate())
when matched
then update set target.salesprice = 1111
when not matched
then insert (
CompanyID,
SalesOrderID,
SalesPrice
)
values (
source.CompanyId,
#column_1_value,
#column_2_value
);
select * from dbo.tblOrders
If you will give me an information, then I can prepare target and source tables properly.